Adaptive optics and compensated imaging systems are generally used to correct aberrations in input laser beams. For example, a laser beam may be transmitted through the atmosphere from a remote source to a receiver or other detector. Atmospherically induced scintillation may cause substantial aberrations of the input beam. Conventional adaptive optics and compensated imaging systems have been employed at receiving sites to correct for such aberrations via performance of wavefront “scrubbing”.
It has been suggested that the presence of amplitude variations due to atmospheric scintillation and device inhomogeneities may substantially degrade the performance of adaptive optical systems in certain operational modes. For example, in a liquid crystal light valve (LCLV), although small amplitude variations may not degrade performance significantly, very large amplitude fluctuations may be considerably problematic. Such an adaptive optical system for phase compensation is generally described by Cardinal Warde et al. in “High Resolution Adaptive Phase Compensation for Low-Visibility Optical Communication”, Proc. IEEE, Vol. 68, pp. 539-545 (1980).
In various military applications, missiles and other guided ordinance may be configured to track and engage targets via remote laser designation; however, atmospherically induced scintillation effects will typically produce guidance errors, causing the ordinance to miss the intended target. This effect is common in fixed-post sensors (e.g., seekers that are not gimbaled).
Corrective beam pointing has been conventionally observed with gimbaled configurations. In these systems, a lens or other optical element may be mounted to a gimbal which is generally free to rotate on at least one axis. Accordingly, the optical configuration may be directed to a desired angle to correct guidance errors as necessary. Unfortunately, the gimbal and supporting actuators substantially add to the cost, complexity and failure susceptibility of the system.
There is a need to correct for scintillation induced optical aberrations while preserving guidance signal amplitude, as compared with what may be otherwise achieved with existing systems.